Electric musical instrument.



M. L. SEVERY & G. B. SINCLAIR.

ELECTRIC MUSICAL INSTRUMENT.

APPLICATION FILED MAY 25,1910.

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M. L. SEVERY & G. B. SINCLAIR.

ELECTRIC MUSICAL INSTRUMENT. APPLICATION FILED MAY 25,1910.

1,098,983, Patented June 2,1914.

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M. L. SBVERY & G. B. SINCLAIR.

- ELECTRIC MUSICAL INSTRUMENT.

APPLICATION FILED MAY 25,1910. 1,098,983, Patented June 2,1914.

3 SHEETS-SHEET 3.

UNITED STATES PATENT OFFICE.

MELVIN L. SEVERY, 0F ARLINGTON HEIGHTS, AND GEORGE B. SINCLAIR, OF MED- I FORD, MASSACHUSETTS, ASSIGNORS A CORPORATION OF MAIN-E.

TO CHOR ALCELO MANUFACTURING COMPANY,

i ELECTRIC MUSICAL INSTRUMENT.

Specification of Letters Patent.

Patented June 2, 1914.

Original application filed August 7, 1905, .Serial No. 273,200. Divided and this application filed Kay 25, 1910. Serial No. 563,437.

To all whom it may concern Be it known that we, MELVIN L. SEvEnY, of Arlington Heights, in the county of Middlesex and Commonwealth of Massachusetts, and GEORGE B. SINCLAIR, of Medford, in the said county and Commonwealth, both citizensof the United States, have invented certain new and useful Improvements in Electric Musical Instruments, of which the following isa specification.

This invention relates to musical instruments wherein tuned sonorous bodies are vibrated by electromagnets to which properly timed electric pulsations are commun1- cated, and this application is divisional from our application filed Aug. 7, 1905, Serial No,

273,200. Previous to our invention, no practical way has ever been devised for securing and delivering to these electromagnets properly timed electric pulsations. Rheotomes, reeds, tuning forks and microphones have all been tried, but they have each failed to produce the desired result, because totally unfitted to the end in view. Some had one set of defects, and others another set, but each and all were unreliable, incapable of tuning, and unable to create strong and properly timed impulses. Prior to our invention, a practical instrument was an impossibility,

for the reason that no one had ever made a a rotative pulsation device winch could convey to said electromagnets sets of pulsations bearing fixed and unchangeable ratios to each other, and the periodicity of each set being in such perfect accord with some one of the vibrational frequencies of its asso' ciated sonorous body as to cause the same to vibrate in perfect synchronism therewith, and to emit a full, true, beautiful and powerful tone. Without this synchronism, the electromagnetic attractions were mutually annihilatory, producing but the slightest Vibration of the associated sonorous body, and that of a periodicity causing the slight tone that was emitted to be false in timbre and of no musical significance. Worse than that, this false quality -of tone was continually changing both in timbre and loudness, being at one instant faint and snarly, at another louder and more dismal, and yet again feebler than before as well as thinner and. more whining, while at no time would it ever be full, true, constant, or in any way dependable. After years of experimentat1on, we finally constructed a-musical instrument of the electromagnetic type where- 1n the frequencies of the magnet pulsations equaled the rates of vibrations of thetuned sonorous bodies associated with the respect ve magnets; to this end devisin a pulsanon-producing means in which t ere is no variation in speed of movement, but in which every pulsation communicated to an electromagnet continues exactly to synchronize with the vibration of the sonorous body controlled thereby, from the beginning of a musical performance upon the instrument until the same is completed.

We speak of our pulsation device as ro-- tating at exactly constant speed and pro ducing 1n the magnets pulsations exactly synchronizing with the vibrations of their associated sonorous .bodies, for the reason that to allintents and purposes such is the case. If it were possible to construct a rotatlng pulsation-producing device whose r0- tations were theoretically. and mathematically absolutely constant, -and whose middle C, for instance, was theoretically and mathematically absolutely 256 pulsations per second, then with-our own device set for the same speed, the best trained human ear in existence would be powerless to detect the;

slightest difference in pitch consequent upon the interruptions, between those of the theoretically perfect device and those of the corresponding interrupter on our own device. Our device therefore insures synchronism of the pulsations in the electromagnets with the vibrations of their associated sonorous bodies. This condition of affairs 3ustifies the use ofthe phraseology herein employed.

Referring to the drawings forming part of this specification, Figure l is a plan view, partly in section, of a pulsation-producing device adapted forpractically perfect synchronism of the magnet pulsations and the free vibrations of the sonorous bodies associated with the respective magnets. Fig. 2 is a sectional detail View of a portion of the synchronizing means. Fig. 3 is a sectional detail view of another part of the same. Fig. 4 is an end-elevation of a part of the synchronizing means. Fig. 5 1s adetail view of the centrifugal contact finger and certain connected parts. I Fig. 6 is a perspective diagrammatic view illustrating the ifiincipie of the complete instrument, the brushes of successive disks being shown out of alinement in order that a plurality may seen.

in Fig. Ii, the reference numeral 1' desig nates a group of toothed disks or rotors connected by reducing gears 2, 3 to a similar group 1 each disk havinga brush 4 contacting therewith for taking the current-1nterruptions adapted for energizing the electromagnets 5 which control the tuned -sonorous bodies or strings 8. Rigid with the group of disks 1 is a cone 6 connected by a belt 7 to a similar but oppositely tapered cone 9. A guide-finger 10 carried by the traveler 11 serves to shift said belt along said cones and so to vary the speed transmitted from one to the other. The power by which the cone 9 is driven is designed to be ample for the maximum eflort of the instrument, and to beunafi'ected by the governing device; the latter acting only to reduce the speed delivered to the toothed disks when the velocity of the motive power becomes too high, and to increase it when too low.- The traveler 11 is mounted on the threaded rod 12 upon the outer end of which is fixed a drum 13. Said drum has two beltgrooves; the one marked 14 being connected by belt 15 to a pulley 16; whilethe groove 17 is joined by belt 19 to the pulley 20. See Figs. 1 and 4. Said pulleys are made to rotate in opposite directions by means of the intermeshing spur gears 21, 22'; the latter being turned by the pinion 23 fixed on the shaft of the:cone 9. Said gear 22 is mounted upon the spindle 24, together with the pulley 20; said pulley and gear being each free to turn upon said spindle and independently of each other, except as influenced by the friction between them and the interposed leather disk 26, incident to the pressure afforded by spring 25. See Fig. 3. The nuts 28 are adjusted on the threaded end of said spindle until the friction is suflicient to cause the ulley 20 to turn the drum 13, and there y move the belt-shifter or traveler 11. Hence the normal action of'said pulley is to shift the belt 7 toward the larger end of the cone 9 and thereby accelerate the speed of the disks 1, and l The gear 21 above referred to is fixed upon its shaft 27 (Fig. 2),

while the pulley 16 is freely mounted thereon.- p This pulley is chambered to inclose both a-leather ring 29 fixed therein, and also a friction disk 30 fixed upon the end of said shaft 27; Attached to the chambered pulley is a diaphragm 31 carrying an armature 32 which is positioned in the field of a fixed electromagnet 33. When said electromagnet is energized, said armature is attracted to bring the ring 29 into frictional contact with the disk 30. This causes said pulley to be contact 39 carried by,

' tuned strings 8.

rotated-by the gear 21, and said ulley to turn the drum 13, inasmuch as the ictional engagement between the disk and leather ring is made greater than that between the ulley 20 and gear 22. To thus energize the electromagnet 33 the instant the speed of the isks 1 begins to rise the slightest possible degree above'normal, the shaft 35 of the cone 6 is provided with a flanged wheel 36, preferably made suficiently heavy to serve as a balance-wheel, and carrying a-centrifugally operated spring contact Fig. 5. At any infinitesimal increase in speed, this arm is moved into touch with the but insulated from, said wheel. This contact is electrically connected with a ring 40 carried by the cone 6 but insulated therefrom, as in Flgs. 1 and 5; this ring is connected by a brush 41 and wire 42 to said electromagnet 33 (Fig. 1), the latter being joined by wire 43 to the source of current 44, and the remainder of the circuit being the wire 45 and the framework and running parts of the machine. Hence the instant the contact arm 37 touches the conarm 37, as shown in tact 39, the circuit between said source and electromagnet-is completed, the latter ener- "gized, and the drum and threaded rod or worm shaft 12 rotated as above described.

This spring contact arm is so adjusted that it will be held almost in touch with the contact 39 so long as the. wheel is revolving at standard speed; but upon the slightest accessionin speed, the increased centrifugal force will carry the arm into engagement with the contact and energize the electromagnet 33.- In actual practice we find this synchronizinzv device exceedingly sensitive;

the two pulleys each acting for a moment,

first one and then the other, to shift the belt 7 back and forth on the two cones 6 and 9, and neitherprdinarily turning more than .a small'fractionof a revolution, the motion being hardly more than a mere tremor.

Referring to Fig. 6, it will be seen that the toothed disk 1,1 of the pulsation device have their brushes 4 connected by wires 51 to the electromagnets 5 which control the The circuit from the source 52 to said disk consists of a wire 53 and brush 54; and the circuit from said source to said electromagnets 5 is through the wire 55 to the contact 56, any one or more of the brushes 57 brought by the keys 59 into touch with said contact, and the wires 60 from said brushes to said electromagnets. By thus causing the pulsation device to exactly accord with the vibrational frequencies of the sonorous bodies 8, the latter are made to speak with a volume, perfection of tone and steadiness of voice never llzpfgre approached in an instrument of the It should be noted that the alternate high and low resistance instrumentalities composing the sections on, the members 1 and 1, as shown in Fig. 1, are substantially of Bqflal o t at 1 length on each said instrumentality, s .the attractive pull given to each sonorous current employed. With any other possible pulse-creating device, as the tuning fork, reed and the ike, previously referred to, the electric contact is always undependable and is usually continued but a small fraction of the time necessary to secure the maximum efficiency, it being absolutely fatal to results if it be continued too long. In other words, with prior devices the current is at its ebb for a much longer time than at its flood, with the result that the sonorous body is iven a mere succession of very short jerks, instead of a series of pulls each lasting entirely during the advance of the said sonorous body toward its actuating electromagnet.

In order that the belt 7 may alwa s contact with the guiding finger 10 so t at the latter shall be the sole controller of the belt, it is necessary to slightly adjust the axes of the two cones out of-parallelism,-as by the adjusting screws 58, as shown in Figs. 1 and 4. The adjustment is such that the lefthand ends of. the cones are farther-apart than their right hand ends.

The position of the spring arm 37 or the relation of its free end to contact 39 (Fig. 5) is adiusted by having the same carried by the sma 1 block 61 pivotally held by the flywheel 36, and having the rear end of sald block pressed outwardly by a slender strut 62 rising obliquely from the sliding collar 63 (Figs. 1 and 5), said collar being pressed from said wheel by a coiled spring 64 upon the shaft 35. A couple of screws 65 made respectively right and left handed, and simultaneously turned by the intermeshing gears 66, enable said collar to be moved in toward the wheel 36 and thereby make said strut more nearly, radial, and said, spring arm slightly farther removed from its associated contact 39. y 'The means illustrated for revolving the cone 9 is a motor 67 connected to the shaft of said cone by grooved pulleys 68, 69 and belt 70.

It will be observed that in the embodiment of our invention here illustrated, no attempt 1 is made to govern the speed of the motor 67,.

ciated with its magnet, when such body is giving off its proper fundamental tone, and this predetermined speed of rotation is maintained by interposing between the rotor and the prime motor, the'controlling'device whereby the speed of rotation is maintained constant, and the pulsations in the respective magnets are synchronized with the vibrations, or rates of vibration, of the sonorous bodies which they actuate. This form or embodiment of our invention is preferred, for the reason that it has been found to give excellent practical results, and because we have encountered less difficulty in directly controlling the rotor by the synchronizer, than in indirectly controlling it by applying the synchronizin or controlling mechanism to the motor. e, however, believe ourselves to be the first to produce any eiiicient or satisfactory means for insuring absolute or substantially perfect synchronism between the frequencies of pulsation of the magnets and the fre uencies or periodicities of vibration '.of then associated sonorousbodies, when the latter give off the tones for which they are tuned. As before stated, rheotomes, tuning forks, and like devices, have been emplo ed in an effort to effect such synchronizing o the magnet pulsations with the periods of vibration of sonorous bodies necessary to the generation of the intended tones. These devices and all others, so far as we are aware, which have been producedfor the purpose, have proven incapable of attaining the end sought, or of producing that perfection of synchronism essential to the generation of full, clear and true tones.

\Ve therefore mean to claim such combinationbroadly, and without restriction to the location of the controlling or synchronizing means. Y

The synchronism of the magnet pulsations and the vibrations of the associated sonorous bodies, resultant upon the use of the synchronizer herein set forth, is so close that the resultant tone is full, clear and true, and no deviation can be discovered by the human ear, or any test so far devised. To all intents and purposes, and so far as can be discovered, the synchronism is perfect, and the accord between the pulsations and the vibrations exact. If there be any deviation whatsoever, it is negligible as measured by the results produced. The term exact hereafter appearing in a claim or claims, is

predetermined speed, to produce v,

. ternatel? hence to be understood as referring to such perfection or approximation to perfect on, as renders detection of anyexisting erroror deviation impracticable by even a trained ear. This explanation is made for thereason that few things performed by human agency can be said to be exact within a 11teral or rigid definition of .the word, though they be so for practlcal purposes.

It has long been common to provide nonmetallic strings ahd other vibrati'n bodies with metallic armatures, which being a1- attracted andrepelled by magnets, or free from attraction, were thrown into musicalvibratiom It is obvious that the same may be, done in the present instance,

and hence it fis to-be understood that the presentinventi'on comprehends as a mag netically attraetable body, any sonorous body, whether it be made of magnetically attractablev material, or merely supplied with an. armature of such material placed within the field, of attraction of the magnet.

- In theforegoing description the lag i of the-string or other sonorous body as related to the impelling force, is not noted, for the reason that such lag is moreor less a controverted matter, and its injection would simply tend to'confusion. The essential point is that Whether the two :be absolutely in phase or there be a lag of the string or sonorous body,,the relationship necessary to generation of theproper tone ismade and maintaincd' 'constant, and the desired result s thereby assured. If there be such lag, 1t

must be uniform, andthe movement if com mcncing later will finish correspondingly later; hence the effect will be that the length of time during wliich' che attractive force is maintained will precisely equal the length of time during which the movement in response to that attraction continues. The foregoing description and the clanns are hence to be read with this understanding.

The synchronizer per se and apart from tuned: sonorous bodies necessary to produce a musical instrument, is made the sub ectmatter of another" application, Serial No.

754,47 5, filed as a renewal or revival of the subject-matter of application Serial No.

273,200, and hence is not claimed herein-encept as part of a complete musical instrument, or' in combination with tuned sonorous bodies, electric circuits, and circuit closers under control of the keys. of the instrument, as hereinaftefexpressed in the claims. The synchronizer per se is hence reserved for said application, Serial N 0. 754,475, filed March 15, 1913. i I

In application Serial No. 619,633, filed April 7th, 1911, (a sole application of M. L. Severy) there is claimed broadly the combi nation with adriven mechanism, of a driving mechanism including a prime movei and a variable power transmission means,

-and means adapted to be controlled by the variation of the speed relation subsisting between said driven and driving mecha- "nisms for varying the'efi'ect of said power 384,872 they are not claimed herein, but are reserved to said earlier application; Like reservation is also made as to matter common to the present application and to our joint application, Serial N 0. 302,331, filed February 23, 1906, and not specifically claimed .herein.

What we claim as our invention and for which we desire Letters Patent is as follows, to wit 1. The combination of a tuned sonorous body; an electromagnet to vibrate the same; a source of electric current; a circuit including said current-source and said electromagnet; a rotative pulsator for said current included in-said circuit; a motor for rotating said pulsator; and a synchronizer interposed between the motor and the pul-. sator, and serving to maintain the latter at a speed aifording pulsations in the magnet of proper frequency to produce in the associated sonorous body, vibrations of the frequency necessary to generate the normal fundamental tone of said body.

2. A musical instrument comprising, in combination, tuned sonorous bodies; electromagnets arranged in attractive relation to said bodies; a source of electric current; a rotor in circuit with the source of electric current and the electromagnets and comcause delivery of electric impulses to the respective electromagnets; a prime motor; and means interposed between said motor and said rotor, whereby the latter is caused 'to rotate constantly at a speed to produce in the respective electromagnets pulsations of such frequencies as will cause vibration of their associated sonorous bodies at the rate necessary to the generation of their normal or fundamental tones.

3. In a musical instrument, in combination, a plurality of tuned sonorous bodies; a plurality of electromagnets respectively arranged in attractive relation to said sonorous bodies; a source of current for said electromagnets; a rotor comprising individual members each included in the circuit of one or an:

posed of individual members adapted to.

such matters are clalmed in said application Serial No.

other of the electromagnets, and each adapt ed to produce at'predetermined speed of rotation, pulsations 1n its magnetof a frequency to cause the sonorous body associated therewith to give 011' vibrations of a frequency to produce some one of the musical tones for which it istuned; a motor for rotating said rotor; and means to maintain constant the predetermined speed of rotation of the ro-" tor, and therebyto synchronize the periodicities of the magnet pulsations with the periodicities of vibration of their associated sonorous bodies requisite to thegeneration of such tones.

4. A musical instrument comprising, in

' combination, a tuned sonorous body; an

electromagnet in attractive relation to the same; a rotating pulsation-producing de-' vice in circuit with said electromagnet; a

source of current for said circuit; a motor for rotating said pulsationroducing de-' vice; and means for contro g said. pulsation-producing device, and maintaining such speed of rotation thereof as shall cause the pulsations in the magnet to be synchronized with the natural vibrational .periods ofthe associated sonorous body. 5. In a musical instrument, the combination of'tuned sonorous bodies; electromagnets in attractive relation thereto; a source, ets; pulsa-' of current for said electrom tion-producingdevices include in the magnet circuits, and ads ted to deliver to each ma et electric imp the frequencies of which are in exact synchronismiwith those' of the free vibrations of the associated sonorous body, the conducting contacts of said pulsation-producin devices being adapted to maintain the ow of current at each impulse, throughout the time oc'cu ied by such associated sonorous body in ma ing itsfia zroach to its actuating electromagnet.

musical instrument comprising, in

combination, sonorous bodies tuned to different pitches; electromagnets adapted to actuate the same; awsource of current for the electromagnets; a. group of pulsation-producing members, each having alternate sections of high and low'resistance, the low resistance sections of each member havin a length bearing definite relation to the equency and duration of contacts necessary to produce vibrations giving the redetermined pitch of the sonorous body wlth which said member is associated; and means for maintaining the low resistance section of each member in conducting relation with the magnet and the source of current during those intervals in which the associated sonorous body, in vibrating to produce its predetermined tone, moves toward its magnet.

norous bod and means whereby the fre- 1 quencies omagnet pulsations are maintained constant, and synchronized with the periodicities of vibration of the sonorous bodies necessary to the generation of their predetermined tones.

8. A musical instrument comprising tuned sonorous bodies; electromagnets respectively arranged in attractive relation to said sonorous bodies; a source of current for said electromagnets;, a rotor interposed between the source of current and the respective electromagnets, and comprising a series of individual members, one for the electromagnet of each sonorous body, each adapted to deliver to its magnetpulsations of the precise frequency necessary to impart to the associated sonorous body vibration of proper periodicity to produce its predetermined tone; a motor for rotating said rotor; and means whereby the speed of said rotor is maintained constant regardless of varia tions in,the speed of the motor.

9 In combination wtih a sonorous'body, an electromagnet for actuating the same; a I source of current for the electromagnet; and 'a pulsation-producing member adapted to deliver current impulses 'to the magnet of duration corresponding to the duration of- 7. A musical instrument comprising, in

the movement of the sonorous body toward 7 the magnet, when said body is vibrating at the rate to produce its predetermined tone. In testimony that We claim the foregolng invention, we have hereunto set our hands this 19th day of May, 1910, and 17th day of May, 1910, respectively.

MELVIN L, SEVERY.

enoncn 1s. smcnam.

Witnesses for Melvin L. Severy:

A. B. UPHAM, G. 'W. Gnocnnn. o

Witnesses for Geo. 18.. Sinclair:

MARGARET F, SINCLAIR, AIR WILLIAMS. 

